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|Title:||(Guanidine) copper complex-catalyzed enantioselective dynamic kinetic allylic alkynylation under biphasic condition||Authors:||Cui, Xi-Yang
Tan, Siu Min
|Keywords:||Science::Chemistry||Issue Date:||2018||Source:||Cui, X.-Y., Ge, Y., Tan, S. M., Jiang, H., Tan, D., Lu, Y., . . . Tan, C.-H. (2018). (Guanidine) copper complex-catalyzed enantioselective dynamic kinetic allylic alkynylation under biphasic condition. Journal of The American Chemical Society, 140(27), 8448-8455. doi:10.1021/jacs.7b12806||Journal:||Journal of the American Chemical Society||Abstract:||Highly enantioselective allylic alkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminal alkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this transformation. Cold-spray ionization mass spectrometry (CSI-MS) and X-ray crystallography were used to identify some catalytic intermediates, which include guanidinium cuprate ion pairs and a copper-alkynide complex. A linear correlation between the enantiopurity of the catalyst and reaction product indicates the presence of a copper complex bearing a single guanidine ligand at the enantio-determining step. Further experimental and computational studies supported that the alkynylation of allylic bromide underwent an anti-SN2' pathway catalyzed by nucleophilic cuprate species. Moreover, metal-assisted racemization of allylic bromide allowed the reaction to proceed in a dynamic kinetic fashion to afford the major enantiomer in high yield.||URI:||https://hdl.handle.net/10356/137033||ISSN:||0002-7863||DOI:||10.1021/jacs.7b12806||Rights:||This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/jacs.7b12806||Fulltext Permission:||open||Fulltext Availability:||With Fulltext|
|Appears in Collections:||SPMS Journal Articles|
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